1. Field of the Invention
The present invention relates generally to screws and more specifically to a self-tapping screw with an improved cutting point which provides superior ability to drill through steel sheet preferably for the metal clad wood building industry.
2. Discussion of the Prior Art
Some self tapping screws have a single cutting point that is disposed at a tip of a screw body. The single cutting point allows a user to drill through steel sheet. If a notch is formed in the tip of the screw body, part of the single cutting point will be lost. The notch improves the ability to drill through the steel sheet and deburrs the newly formed hole. An example of a single cutting point screw is found in U.S. Pat. No. 4,329,099 to Shimizu, et al. The cutting point is actually part of the thread which continues to the end of the screw body. The screw has a short second thread which does not continue to the tip. However, the Shimizu, et al. patent does not have a notch; a notch greatly improves the ability to drill through steel sheet. It is also easier to drill through steel with two flutes instead of one. Greater stability is obtained by using two flutes especially when drilling by hand.
Accordingly, there is a clearly felt need in the art for a self-tapping screw with an improved cutting point which has at least one cutting point that continues to the tip and also has a notch to improve the drilling and deburring ability of the self-tapping screw.